MICR102A - Staphylococcus

grows in clusters like a bunch of grapes

staphylococcus

what is the approximate size of staphylococcus?

0.5 to 1 µm (micrometer) in diameter

true or false

staphylococcus is a perfectly spherical Gram (+) cocci

true

what are the two (2) pigmented colony type of staphylococcus?

S. aureus and S. epidermidis

which pigmented colony type of staphylococcus is golden yellow in color?

S. aureus

which pigmented colony type of staphylococcus is white in color?

S. epidermidis

what is the other term for S. epidermidis?

S. albus

S. aureus common habitat includes? (4)

nasal passages, skin, oral cavity, and intestinal tract

"nasal skin, oral invasion"

S. epidermidis/albus common habitat includes? (1)

they are inhabitants of the skin

is a disease causing process

other definition: refers both to the mechanism of infection and to the mechanism by which disease develops.

pathogenesis

true or false

virulence factors help bacteria to (1) invade the host, (2) cause disease, and (3) evade host defenses

true

many bacteria are surrounded by ________ that protect them from opsonization and phagocytosis.

capsules

_____________ are iron-binding factors that allow some bacteria to compete with the host for iron, which is bound to hemoglobin, transferrin, and lactoferrin.

siderophores

_______ is the measure of the pathogenicity of an organism

virulence

give the virulence factors (3)

surface proteins, factors that inhibit phagocytosis, protein toxins

this virulence factor promotes colonization of host tissues such as those that promote attachment to host

surface proteins

give example of surface proteins that promotes attachment to the host and forms part of the extracellular matrix (2)

laminin and fibronectin

true or false

fibronectin is present on epithelial and endothelial surfaces

true

true or false

fibronectin is not part of the components of blood clot

false.

true or false

fibrinogen/fibrin binding promotes attachment to blood clots and traumatized tissues

true

what are factors that inhibit phagocytosis? (2)

capsule, immunoglobulin-binding protein A

found on the surface of S. aureus as serotype 5 or 8 polysaccharides.

capsular polysaccharide

capsular polysaccharide is known as a _______ because it requires electron microscopy with antibody labeling for visualization.

microcapsule

true or false

capsular polysaccharide is rapidly lost during laboratory subculture.

true

true or false

capsular polysaccharide's function remains unclear but may play a role in impeding/hindering phagocytosis to enhance bacterial survival.

true

a toxin that specifically acts on polymorphonuclear leukocytes

other info: ________ refers to toxins that target and damage leukocytes, and their effect is to cause cell lysis by forming pores in the cell membranes.

leukocidin

these are membrane damaging toxins that are responsible for the symptoms during infections

protein toxins

what are the types of protein toxins

Alpha toxin, Beta toxin, Delta toxin, Gamma toxin, and Leucocidin

the most potent membrane-damaging toxin; a major virulence factor.

it binds to cell membranes and forms hexameric rings which creates pores for cellular leakage.

true or false

alpha toxin has a high affinity for human platelets and monocytes

true

alpha toxin triggers the release of _____________ and ___________, causing inflammatory mediators and septic shock symptoms.

eicosanoids and cytokines

are chemical signals produced by the body from fatty acids. they play a role in inflammation and other immune responses.

eicosanoids

are proteins that help regulate immune responses and cell communication. they play a key role in inflammation, infection response, and cell growth.

cytokines

a life-threatening condition where the body has an extreme response to an infection, causing widespread inflammation and potential organ damage.

sepsis

a more severe stage of sepsis, where the body's blood pressure drops dangerously low, leading to organ failure. It's a medical emergency and can be fatal without immediate treatment.

septic shock

in short, septic shock is a compilation of sepsis

a protein toxin that specifically targets sphingomyelin

beta toxin

B-toxin is a sphingomyelinase (specifically Sphingomyelinase C), meaning it breaks down _______________, a lipid found in the cell membranes of certain host cells.

sphingomyelin

a small peptide toxin produced by most S. aureus strains and it's role in disease is not well understood

delta toxin

true or false

delta toxin is also a sphingomyelinase

false. delta toxin is a phospholipase meaning it breaks down phospholipids

are two-component protein toxins that damages cell membranes.

they are produced separately but acts together to damage membranes.

gamma-toxin and leukocidin

gamma-toxin produces 3 proteins (3)

proteins: A, B, and C

true or false

gamma-toxin produces the ff combination:

B and C forms leukotoxin with poor hemolytic activity.

A and B are hemolytic and weakly leukotoxic.

true

panton and valentine (PV) leucocidin distinct from leukotoxin by ________ _____; has potent leukotoxicity but non-hemolytic

gamma locus

this an important factor in necrotizing skin lesions such as dermonecrosis when injected SC in rabbits

additional definition: this is a toxin produced by S. aureus that is distinct from leukotoxin in its genetic and functional characteristics

panton-valentine leukocidin (PV/PVL)

refers to the ability to stimulate the immune system.

immunostimulatory

these are toxic proteins secreted by bacteria into their surroundings.

exotoxins

a ____________ is essentially a toxin that hijacks the immune system, causing it to overreact and harm the body instead of defending it which makes them extremely potent and dangerous.

superantigen

give an example of a superantigen

enterotoxin and TSST1

this superantigen has 6 serotypes and it can cause diarrhea and vomiting (staphylococcal food poisoning)

enterotoxin

enterotoxin has six (6) serotypes

a, b, c, d, e, and g

true or false

enterotoxin cannot cause toxic shock syndrome

false.

refers to the ability of a substance to induce vomiting

emetic activity

this superantigen is responsible for 75% of TSS including menstrual cases; tampon-related TSS not true infection

TSST1

true or false

TSST1 does not have any emetic ability

true

true or false

superantigens stimulate T-cells without normal antigenic recognition, results to release of cytokines in large amounts causing symptoms of TSS

true

this causes scalded skin syndrome in neonates with widespread blistering and loss of epidermis

epidermolytic/exfoliative toxin (ET)

epidermolytic toxin has two forms (2)

ETA (Exfoliative Toxin A) and ETB (Exfoliative Toxin B)

a traditional marker for S. aureus

another info: an extracellular protein which binds with prothrombin in host to form staphylothrombin which causes the activation of the protease activity of thrombin resulting to conversion of fibrinogen to fibrin and formation of clot in plasma

coagulase

an enzyme that is important in abscesses where it could modify antibacterial lipids and prolong bacterial survival

fatty acid modifying enzyme (FAME)

enzymes that provides nutrients for bacteria (3)

proteases, lipases, deoxyribonuclease (Dnase)

hydrolyzes hyaluronic acid (cementing substance)

hyaluronidase

true or false

hyaluronidase is a spreading factor

true

the most important coagulase-negative staphylococci (CNS) which is a common commensal of the skin

S. epidermidis

true or false

S. aureus is the major cause of infections associated with prosthetic devices and catheters

false. S. epidermidis.

S. epidermidis is associated with the production of characteristic slime (biofilm)

true

true or false

S. epidermidis ferments mannitol, S. aureus does not

false S. aureus ferments mannitol, S. epidermidis does not

give three out of the seven diseases associated with S. aureus

1. Botryomycosis in horses

2. Mastitis

3. Tick pyemia in lambs

4. Facial or periorbital eczema in sheep

5. Purulent synovitis in poultry

6. Cutaneous staphylococcosis

7. Porcine necrotizing staphylococcal endometritis

a staphylococcus specie that is an opportunistic invader

S. epidermidis

a staphylococcus specie most prevalent in dogs and carnivores

S. intermedius

a staphylococcus specie that has the ff characteristic:

• Exudative epidermitis of swine

• Thru breaks on the skin

• Moist, greasy exudate on entire body of animal

• Biotin requirement

S. hyicus subsp. hyicus

what are the types of diagnosis for staphylococcus? (5)

1. smears

2. culture on BAP

3. mannitol salt agar (MSA)

4. coagulase

5. deoxyribonuclease

true or false

currently there is no effective vaccines against staphylococcus

what are the antimicrobial resistance of staphylococcus?

1. beta lactamase

2. methicillin resistant S. aureus (MRSA) or multiple-drug resistant

beta hemolysis (β)

identify what type of hemolytic activity

alpha hemolysis (α)

identify what type of hemolytic activity